/ frɒst; NAmE frɔːst/ noun , verb
■ noun
1.
[ U , C ] a weather condition in which the temperature drops below 0°C (= freezing point ) so that a thin white layer of ice forms on the ground and other surfaces, especially at night :
It will be a clear night with some ground frost .
a sharp / hard / severe frost
There were ten degrees of frost (= the temperature dropped to -10°C) last night.
frost damage
2.
[ U ] the thin white layer of ice that forms when the temperature drops below 0°C :
The car windows were covered with frost.
—see also hoar frost
■ verb
1.
frost (sth) (over / up) to cover sth or to become covered with a thin white layer of ice :
[ vn ]
The mirror was frosted up.
[ v ]
The windows had frosted over.
2.
[ vn ] ( especially NAmE ) to cover a cake with icing / frosting
••
WORD ORIGIN
Old English frost , forst , of Germanic origin; related to Dutch vorst and German Frost , also to freeze .